71 lines
2.5 KiB
C++
71 lines
2.5 KiB
C++
// Source : https://leetcode.com/problems/unique-email-addresses/
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// Author : Hao Chen
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// Date : 2020-07-26
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/*****************************************************************************************************
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*
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* Every email consists of a local name and a domain name, separated by the @ sign.
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*
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* For example, in alice@leetcode.com, alice is the local name, and leetcode.com is the domain name.
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*
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* Besides lowercase letters, these emails may contain '.'s or '+'s.
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*
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* If you add periods ('.') between some characters in the local name part of an email address, mail
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* sent there will be forwarded to the same address without dots in the local name. For example,
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* "alice.z@leetcode.com" and "alicez@leetcode.com" forward to the same email address. (Note that
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* this rule does not apply for domain names.)
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*
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* If you add a plus ('+') in the local name, everything after the first plus sign will be ignored.
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* This allows certain emails to be filtered, for example m.y+name@email.com will be forwarded to
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* my@email.com. (Again, this rule does not apply for domain names.)
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*
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* It is possible to use both of these rules at the same time.
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*
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* Given a list of emails, we send one email to each address in the list. How many different
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* addresses actually receive mails?
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*
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* Example 1:
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*
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* Input:
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* ["test.email+alex@leetcode.com","test.e.mail+bob.cathy@leetcode.com","testemail+david@lee.tcode.com"
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* ]
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* Output: 2
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* Explanation: "testemail@leetcode.com" and "testemail@lee.tcode.com" actually receive mails
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*
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* Note:
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*
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* 1 <= emails[i].length <= 100
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* 1 <= emails.length <= 100
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* Each emails[i] contains exactly one '@' character.
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* All local and domain names are non-empty.
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* Local names do not start with a '+' character.
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*
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******************************************************************************************************/
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class Solution {
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public:
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int numUniqueEmails(vector<string>& emails) {
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unordered_map<string, int> dict;
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for (auto& email : emails) {
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string addr;
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for(int i=0; i<email.size(); i++) {
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if (email[i] == '.' ) continue;
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if (email[i] == '+') {
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while( email[++i] != '@');
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}
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if (email[i] =='@') {
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addr += email.substr(i);
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break;
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}
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addr += email[i];
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}
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dict[addr]++;
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}
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return dict.size();
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}
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};
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